When washing clothing fully or in part made of delicate natural fabrics like silk or wool there may be a conflict between the desire to protect and care for the fabrics and the desire to obtain clean clothing. This may especially be relevant when the clothes in question are such as lingerie or underwear.
Traditionally, underwear, bed sheets or kitchen towels have been washed at temperatures of 60 or 95° C., in order to obtain both visually and hygienic clean laundry. Over the years laundry detergent product have been developed that comprise enzymes, such as proteases, amylases, lipases, and cellulases; these laundry detergents are marketed for washing at lower temperatures such as 30 or 40° C. as the enzymes aids in the washing process. Recently, low-temperature detergents have been developed that may be used at temperatures as low as 15-20° C., these contain newly developed enzymes aiding the washing process.
In the particular case with wool and silk textiles, the natural polymer on which the textile fiber is based is a protein and thus susceptible to degradation by the enzyme. In fact, depending on the enzyme and the washing conditions, there is a real risk of the fabrics being gradually eaten by the enzymes. Enzyme based detergents are not recommended for wool and silk containing textiles.
Presence of microorganisms in textiles or other materials may provide a health hazard. The Danish National Consumer Agency has stated that it in certain instances is necessary to do laundry at 95° C. This is for example in cases of infectious diseases, in cases with particularly dirty textiles, such as diapers, and when laundering textiles comprising sources of infection. Such sources of infection may be faeces, urine, blood, body fluids, etc. The temperature of 95° C. is to ensure elimination of such sources of infection, which modern enzyme containing laundry detergents suitable for washing at e.g. 40° C. do not ensure.
There has recently furthermore been an increased focus on the possibility of cross-contamination from one batch of laundry to the next. If for instance one person has used a washing machine on e.g. 40° for textiles carrying a source of infection, and the next person uses the same washing machine for washing at low temperature as well, e.g. delicate textiles such as lingerie at 30° C., there may be transferred microorganisms from one laundry batch to the next. This is for example a risk in apartment blocks with communal laundries, at launderettes, or especially at communal laundries in nursing homes or hospitals with a majority of ill or frail persons susceptible both to provide the infection or easily gain an infection from cross-contaminated clothes, bed linen or towels washed in a communal laundry.
Accordingly, in order to obtain a satisfying laundry of e.g. lingerie or underwear, it is necessary to wash at at least 60° C. However, the manufactures of lingerie, or other delicate textiles, provide care labels prescribing a washing temperature of 40° C. or less. The lack of washing at sufficiently high temperature gives rise to the above-mentioned problems of cross-contamination or an actually continued re-infection of the same person. This may for instance be the case with genital fungal infections that in some may become chronic, or vaginitis in general, such as e.g. both candidiasis or bacterial vaginosis. Sources of infection are for example bacteria (such as e.g. Streptococcus, Staphylococcus aureus, Gardnerella, Escherichia coli, bacteriods, or mycoplasma), fungi (such as e.g. Candida albicans), or vira (such as e.g. HIV-1, Hepatitis B or Hepatitis C).
In addition to being sensitive towards enzymes, wool and silk textiles also need to be washed at low temperatures of for example 30 or 40° C. and at gentle cycle in washing machine or gently by hand wash, in order to avoid excessive shrinkage or deformation. It is further recommended to avoid heavily alkaline pH. Therefore, a laundry detergent for delicate fabrics, such as silk and wool, needs to be enzyme free, less alkaline than traditional laundry detergents and suitable for washing at low temperatures.
The above stated problems with cross-contamination or re-infection are therefore especially relevant for such delicate textiles. Accordingly, unless the clothing items are only lightly soiled and there is no risk of infectious sources, there is a conflict between caring for the fabric and obtaining clean clothing. When the clothing items are such as lingerie or underwear there is special need for a delicate laundry detergent that in addition to washing and caring for the fabric also can remove any undesired remains of bacteria, fungi or vira.
Due to the chemical nature of both laundry detergent ingredients and biocidal compounds, it is well-known that not all combinations of such ingredients may provide a stable and effective composition that both provides detergent and biocidal properties.
Another well-known problem in the field of cleaning products is that rather high concentrations of products comprising a single biocide are required and that the target microorganisms are likely to get resistant towards the biocide used upon long-term treatment.